Some of recording apparatuses, for example, electrophotographic printers use an intermediate transfer drum (intermediate transfer medium) for the purpose of color printing. The intermediate transfer drum is usually formed with a conductive rubber layer on the surface of a metallic drum, so that the surface of the drum is not flat, having small irregularities of about several tens of microns.
Generally, the intermediate transfer drum is pressed against a photosensitive drum (latent image carrier), and toner images developed on the photosensitive drum are transferred to the intermediate transfer drum, so that the intermediate transfer drum must be in line contact with the photosensitive drum in the width direction.
However, if the intermediate transfer drum has small irregularities on the surface of the rubber layer thereof, a non-contact portion is produced between the photosensitive drum and intermediate transfer drum, so that the contact in the width direction consists partially of point contact. If such point contact occurs, the toner image is not transferred from the photosensitive drum to the intermediate transfer drum at the non-contact portion where the photosensitive drum is not in contact with the intermediate transfer drum, that is, transfer nonuniformity occurs. Therefore, there arises a problem in that the image quality of the resultant color print decreases remarkably.
If the intermediate transfer drum is pressed against the photosensitive transfer drum with a high pressing force, such point contact can be averted by the elastic deformation of the rubber layer.
However, if the pressing force is too great, the photosensitive layer consisting of an organic photoconductor (OPC) formed on the surface of the photosensitive drum deteriorates, or a dot tailing phenomenon such that the toner image transferred to the intermediate transfer drum collapses occurs. Therefore, there arises a problem of decrease in quality of the resultant image or other problems.
The present invention was made in view of the above situation, and accordingly an object thereof is to provide a recording apparatus and method in which high-quality images can be obtained without the occurrence of transfer nonuniformity when toner images are transferred from the latent image carrier to the intermediate transfer medium.